ASTM A194 Grade 2H Heavy Hex Nuts
ASTM A194 Grade 2H heavy hex nuts — medium-carbon steel, quenched and tempered, 175 ksi proof-load stress at C24–C38 Rockwell across 1/4" to 4". The A193 B7 stud-bolt partner for refinery and pipeline service.
Last updated: 2026-11
Specifications
Grade 2H is the ASTM A194 grade that structural and petrochemical bolting reaches for: a medium-carbon steel nut, quenched and tempered to 175 ksi proof-load stress at C24–C38 Rockwell, running 1/4" through 4" nominal size in the heavy hex pattern. On the compatibility chart it is accepted across the structural bolt set — A325 Type 1 and A490 Type 1 both take 2H, and a hot-dip galvanized A325 calls for 2H or A563 DH. In stud-bolt service it is the default: A193 B7 studs with A194 2H heavy hex nuts are the standard pairing for general refinery and pipeline work.
| Standard | ASTM A194 — Grade 2H |
|---|---|
| Material | Medium-carbon steel, quenched and tempered |
| Size range | 1/4" – 4" |
| Proof-load stress | 175 ksi |
| Hardness | C24–C38 Rockwell |
| Grade pairing | A325 Type 1 and A490 Type 1 accept 2H; hot-dip galvanized A325: 2H or A563 DH |
| Stud pairing | A193 B7 studs with A194 2H heavy hex nuts — the default for general refinery and pipeline service |
| Nominal size | Threads per inch | Stress area (in²) | Proof load (lbf) |
|---|---|---|---|
| 1/4 | 20 | 0.0316 | 5570 |
| 5/16 | 18 | 0.0524 | 9170 |
| 3/8 | 16 | 0.0774 | 13560 |
| 7/16 | 14 | 0.1063 | 18600 |
| 1/2 | 13 | 0.1419 | 24830 |
| 9/16 | 12 | 0.182 | 31850 |
| 5/8 | 11 | 0.226 | 39550 |
| 3/4 | 10 | 0.334 | 58450 |
| 7/8 | 9 | 0.462 | 80850 |
| 1 | 8 | 0.606 | 106000 |
| 1-1/8 | 8 | 0.79 | 138200 |
| 1-1/4 | 8 | 1 | 175000 |
| 1-3/8 | 8 | 1.233 | 215800 |
| 1-1/2 | 8 | 1.492 | 261100 |
| Nominal size | Threads per inch | Stress area (in²) | Proof load, 2H heavy hex (lbf) |
|---|---|---|---|
| 1-5/8 | 8 | 1.78 | 311500 |
| 1-3/4 | 8 | 2.08 | 364000 |
| 1-7/8 | 8 | 2.41 | 421800 |
| 2 | 8 | 2.77 | 484800 |
| 2-1/4 | 8 | 3.56 | 623000 |
| 2-1/2 | 8 | 4.44 | 777000 |
| 2-3/4 | 8 | 5.43 | 950250 |
Where this grade fits
2H is the quenched-and-tempered 175 ksi heavy hex nut for high-strength stud work: the default partner for A193 B7 studs in refinery and pipeline service, and accepted with A325 Type 1 and A490 Type 1 structural bolts. Because it is hardened, coating choices follow the same embrittlement constraints as the high-strength bolt it pairs with.
Deep read: Pairing a Nut to a Bolt: Property Class, Height, Engagement and Flange vs Hex
Materials
- Medium-carbon steel
Ordering & documentation
Documents
Shipments are backed by Mill Test Certificate (MTC), Dimensional Report, Salt Spray Test Report on request, with full batch traceability from raw material to finished product. Quality management follows the owner-confirmed compliance list: ISO 9001:2015, RoHS, REACH. Exact document sets are confirmed on the order.
Quotation
- The fastener family (ASTM A194 Grade 2H Heavy Hex Nuts) plus the standard designation from your drawing — DIN / ISO / JIS / ASTM / ANSI, or a drawing for custom parts.
- Size (diameter and length), thread type (metric or inch), property class or grade, and coating or finish.
- Quantity per size and your target delivery date.
- Destination country, and any required documents (for example a mill test certificate) so the quote includes them.
Sample & supply
Minimum order quantity is 10,000 pieces. Stock items run 3–7 days. Quantities or variants outside the standard range are confirmed at quotation.
Storage & shipping
Parts are packed for export and shipped factory-direct to buyers in Europe, Asia, the Americas and the Middle East. Store fasteners dry and protected until installation, and keep coated parts in their packaging until use; specific packing and preservation requirements can be stated on the order and confirmed at quotation.
Frequently asked questions
A194 2H or A563 DH — which structural nut grade?
On the collected grade chart the two sit at the same numbers: both deliver 175 ksi proof-load stress at C24–C38 Rockwell over 1/4"–4", and both appear on the A325/A490 compatibility chart (galvanized A325 accepts either 2H or DH). The choice is therefore specification-driven, not strength-driven: order the designation the engineer of record called out. Where the assembly is A193 B7 stud bolting, the callout is conventionally A194 2H.
What is the MOQ and lead time for this nut type?
The minimum order quantity is 10,000 pieces. Stock items ship in 3–7 days; non-stock items are confirmed at quotation. Common diameters in this nut type are widely stocked; confirm the exact schedule against quantity and size mix at quotation.
What should an RFQ for this nut type state?
State the standard designation (for example DIN 985 or DIN 6923), nominal thread size and pitch (metric coarse unless fine pitch is required), material and strength pairing with the mating bolt, finish (plain, zinc, or hot-dip galvanized where compatible), required certificates such as a mill test report per EN 10204 3.1, and quantity per size — plus destination country.
Request a Quote
Get factory-direct pricing from the manufacturer.
What to include in your inquiry
- ✓ Standard and property class (e.g. DIN 912, ISO 4762, class 8.8) — or a drawing for custom parts.
- ✓ Sizes, lengths and thread type (metric or inch).
- ✓ Quantity per size and your target delivery date.
- ✓ Destination country, plus any coating or finish requirement.
- ✓ Any documents you need with the shipment (e.g. mill test certificate) so the quote includes them.
- ✓ Your inquiry goes straight to the factory team by email and gets a reply within 24 hours.
- ✓ Factory-direct pricing
- ✓ Standard and custom specifications
- ✓ Factory-direct export to buyers in Europe, Asia, the Americas and the Middle East
- ✓ Full fastener family support